The effects of cooling on experimental free flap survival.

Cooling to 6-7 degrees significantly increases ischaemic tissue survival to 48 and, probably, 72 hours. Inflammatory changes develop in direct proportion to the duration of the cold ischaemia time. The skin and vessels within the flap appear to be minimally affected by cold ischaemia while fat and muscle demonstrate significant necrosis, inflammation and ultimate fibrosis. Very little, if any, muscle survives the ischaemic insult studied in this model.